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Tick, tock goes the quantum clock

CAN a pendulum swing in space? It might if it is quantum powered, a fact that could be exploited to build tiny timepieces that run off the quantum fluctuations that occur in a vacuum.

Habibollah Razmi and Mah Abdollahi from the University of Qom, Iran, envisaged a tiny pendulum made with a string of 30 atoms attached to a conducting plate at one end. They calculated that the Casimir-Polder force – which arises from the exchange of the “virtual” photons that pop in and out of existence in a vacuum – would attract the nanostring towards the plate. Before it …